Repositório Comunidade:http://hdl.handle.net/10362/3551
Sun, 18 Feb 2018 06:47:10 GMT2018-02-18T06:47:10ZThe Relevance of Ribonuclease III in Pathogenic Bacteriahttp://hdl.handle.net/10362/12027
Título: The Relevance of Ribonuclease III in Pathogenic Bacteria
Autor: Saramago, Ana Margarida Teixeira
Resumo: Ribonucleases (RNases) are key factors in the control of all biological
processes, since they modulate the stability of RNA transcripts, allowing rapid
changes in gene expression. Some RNases are up-regulated under stress
situations and are involved in virulence processes in pathogenic microorganisms.
RNases also control the levels of regulatory RNAs, which play very important
roles in cell physiology.(...)
Descrição: Dissertation presented to obtain the Ph.D degree in Biology.Sun, 01 Dec 2013 00:00:00 GMThttp://hdl.handle.net/10362/120272013-12-01T00:00:00ZInterplay of Exoribonucleases, Hfq and Small RNAs Structural Determinants in the Control of Gene Expressionhttp://hdl.handle.net/10362/10590
Título: Interplay of Exoribonucleases, Hfq and Small RNAs Structural Determinants in the Control of Gene Expression
Autor: Pobre, Vânia Sofia Fidalgo
Resumo: Small non-coding RNAs (sRNAs) are regulatory molecules that typically are
not translated into proteins. These molecules are often highly structured and very
stable and can affect many genetic pathways in all domains of life. Bacterial small
regulatory RNAs (sRNAs) parallel microRNAs in their ability to control multiple
targets. Small RNAs can bind to proteins or to mRNA targets. The sRNAs that act
by an antisense mechanism can have full (cis-encoded) or partial complementarity
(trans-encoded) with their targets. Most of the trans-encoded sRNAs studied so
far in Escherichia coli bind the RNA chaperone Hfq. The 5’ end of antisense RNAs is
usually found to be critical for the interaction with targets, generally inhibiting
translation and promoting mRNA decay. RNases are key elements in the control of
RNA levels in the cell and not surprisingly are also critical in the regulation of
sRNAs. In E. coli there are three 3’-5’exoribonucleases that accomplish most of the
mRNA exodegradative activity: ribonuclease II (RNase II), ribonuclease R (RNase R)
and polynucleotide phosphorylase (PNPase).(...)
Descrição: Dissertation presented to obtain the Ph.D degree in BiologySat, 01 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10362/105902012-12-01T00:00:00ZThe Role of Small RNAs and Ribonucleases in the Control of Gene Expression in Salmonella Typhimuriumhttp://hdl.handle.net/10362/10589
Título: The Role of Small RNAs and Ribonucleases in the Control of Gene Expression in Salmonella Typhimurium
Autor: Silva, Inês de Jesus de Almeida
Resumo: RNAs are important effectors in the process of gene expression. In
bacteria, the levels of the transcripts have to be rapidly adjusted in response to
constantly changing environmental demands. The cellular concentration of a
given RNA is the result of the balance between its synthesis and degradation.
RNA degradation is a complex process encompassing multiple pathways.
Ribonucleases are the enzymes that directly process and degrade RNA
transcripts, regulating their cellular amounts. The rate at which RNA decay
occurs depends on the availability of ribonucleases and their specificities
according to the sequence and/or the structural elements of the RNA molecule.
Several other factors modulate RNA degradation, namely polyadenylation, which
plays a multifunctional role in RNA metabolism. Additionally, small non-coding
RNAs are crucial regulators of gene expression, and can directly modulate the
stability of their mRNA targets. In many cases this regulation is dependent on
Hfq, an RNA binding protein which can act in concert with polyadenylation
enzymes and is often necessary for the activity of the sRNAs.(...)
Descrição: Dissertation presented to obtain the Ph.D degree in BiologySat, 01 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10362/105892012-12-01T00:00:00ZBiological and Biochemical Characterization of Mutants of the RNase II family of enzymeshttp://hdl.handle.net/10362/9921
Título: Biological and Biochemical Characterization of Mutants of the RNase II family of enzymes
Autor: Reis, Ana Filipa de Melo Tadeu Pereira dos
Resumo: The cellular concentration of a given RNA is the result of the balance between its
synthesis and degradation. RNA degradation plays a fundamental role in RNA
metabolism, since the fast turnover of mRNA is important for the control of gene
expression. One of the key components of RNA metabolism are enzymes from the
RNase II family.(...)
Descrição: Dissertação para a obtenção de grau de doutor em Biologia pelo Instituto de Tecnologia Química e Biológica. Universidade Nova de Lisboa.Sat, 01 Dec 2012 00:00:00 GMThttp://hdl.handle.net/10362/99212012-12-01T00:00:00Z